Sulfur-containing lubricant inhibited against staining



United States Patent@ SULFUR-CONTAINING LUBRICANT INHIBITED AGAINSTSTAINING Howard M. Rue, Media, Pa., assignor to Sun Oil Company,Philadelphia, Pa., a corporation of New Jersey No Drawing. Filed Oct.11, 1956, Ser. No. 615,233

Claims. (Cl. 252-34.7)

This invention relates to sulfur-containing lubricants normally tendingto stain ferrous metals, which lubricants contain a plurality ofadditive materials to reduce the staining tendency.

Sulfur-containing lubricants constitute a well known' class oflubricants, the sulfur content providing extreme pressure properties andother beneficial properties as well known in the art. One common use ofsulfur-containing lubricants is as cutting fluids of the non-emulsiontyp for use in metal working operations.

A diflicult problem encountered in the use of sulfurcontaininglubricants, particularly as cutting fluids, is

the tendency of such lubricantsto stain ferrous metals or other types ofmetals with which they come in contact in the presence of moisture.Various means have been proposed for overcoming the staining tendency,and

some of these means apparently give satisfactory results when the oilsare subjected to relatively mild staining tests. However, under moresevere conditions tending to result in staining, measures which aresatisfactory under milder conditions frequently do not providesatisfactory results.

According to the invention, a plurality of additives are employed in asulfur-containing lubricant in order to provide a lubricatingcomposition which is remarkably free from staining tendency even undersevere testing conditions.

The additives employed in combination according to the invention are (l)a partial ester of a polyhydric alcohol, which ester has 14 to 56 carbonatoms per molecule, and (2) an acyclic polyamine having 12 to 28 carbonatoms per molecule. In one embodiment of the invention, the secondadditivecomprises a salt of the acyclic polyamine with an organiccarboxylic acid having 12 to 30 carbon atoms per molecule.

It is essential according to the invention that the specified additivesbe employed in combination. Neither additive alone is capable ofpreventing staining under severe testing conditions, whereas thecombination of additives is highly eifective even under severe testingconditions.

Any suitable polyhydric alcohol having two or more hydroxyl groups permolecule, can be employed in the preparation of the ester additiveaccording to the invention. Examples of suitable ester-formingpolyhydric alcohols are glycols such as ethylene glycol, propyleneglycol, butylene glycol, 1,5-pentanediol, 1,6-hexanediol, diethyleneglycol, triethylene glycol and higher analogs; glycerol;pentaerythritol; sorbitol; mannitol, etc. Glycerol is a'preferredpolyhydric alcohol for preparation of the ester additive. For furtherdisclosure of polyliydric alcohols, reference is made to R. E. Kirk etal., Encyclopedia of Chemical Technology, volume 1 (1947), page 308,Tables II and III, and pages 321 to 333.

The ester additive contains unesterified hydroxyl groups. Alkoxylatedderivatives of the esters, prepared ice by reaction of alkylene oxideswith one or more of the 1 free hydroxyl groups, can be employed ifdesired.

The polyhydric alcohol partial ester employed is capable of acting as awater-in-oil emulsifying agent, and

accordingly has hydrophile-lipophile balance (HLB), as

defined in an article by W. C. Griifin, in Journal of the Society of-Cosmetic Chemists, volume 1, page 311 (1949), within the approximaterange from 3 to 6. Examples of polyhydric alcohol partial esters whichare suitable for use according to the invention are glycerol monooleate,sorbitan monostearate (Atlas Powder Com panys Span 60), sorbitanmonooleate (Atlas, Span 80), sorbitan sesquioleate (Atlas Arlacel C),poly oxyethylene sorbitol tetraoleate having viscosity of 200- 300 cp.at 25 C. and specific gravity of 0.92-0.98

, be made more hydrophilic (i.e. higher HLB) in a given instance byintroducing polyoxyalkylene radicals into the molecule. Or the moleculemay be made more lipophilic' (i.e. lower HLB) by introducing additionallong chain fatty acid radicals into the molecule or by increasing thechain length of the fatty acid radical or HLB than sorbitan monooleate,and the latter has lower HLB than sorbitan monolaurate. The number ofhydroxyl groups in the polyhydric alcohol has an effect on the HLBvalue, free hydro-xyl groups generally increasing the HLB value. Byproper adjustment of these factors, a person skilled in the art canmake, in addition to the specific esters mentioned above, numerous otherwater-in-oil emulsifying agents suitable for use according to theinvention.

Any suitable organic monocarboxylic acid can be employed in thepreparation of the ester additive. Thus, the acid can be an aromatic,aliphatic, cycloaliphatic or heterocyclic carboxylic acid. Preferredacids are: the naturally occurring fatty acids, more preferably thosehaving 12 to 30 carbon atoms per molecule, e.g. lauric, myristic,palmitic, oleic, stearic, erucic acids, etc.; petroleum naphthenicacids; rosin acids; and mixtures of carboxylic acids obtained by thepartial oxidation in liquid phase of hydrocarbon mixtures such aspetroleum fractions, as disclosed in L. W. Jones United States PatentNo. 2,756,211 issued July 24, 1956, and the disclosures referred to inthe specification of that patent. Other types of acids can be employedto make the ester additive, e.g. benzoic acid, furoic acid, etc.However, the acids previously mentioned are preferred.

The number of carbon atoms in the acid varies according to the nature ofthe rest of the molecule, that number being one of a plurality offactors influencing HLB. Thus, for example, in the case of glycerolmonoesters and the other esters previously specifically disclosed, theacid or acids preferably have 16 to 22 carbon atoms per molecule, or anaverage of 16 to 22 carbon atoms per molecule. In other esters, higheror lower molecular weight acids may be required, as readily determinableby a person skilled in the art. a

The polyamine additive employed according to the invention contains twoor more amino groups'per molecule and preferably has at least oneprimary amino group in the molecule, and also preferably contains atleast Patented Apr. 18, 1961 vention can be prepared in any suitablemanner.

two amino groups other than a tertiary amino group. Particularlysuitable polyamines are diamines having one primary amino group and onesecondary amino group.

The polyarnine; can contain any suitable number of nitrogen atoms permolecule, though generally this number does not exceed 10, and morepreferably, the number of nitrogen-atoms is not greater than 5. Thepolyamine may contain hydroxyl' groups in addition to nitrogen atoms,though preferably the 'polyamine contains only carbon, hydrogen, andnitrogen in the molecule. Alkoxylated derivatives containing --(CH CHO),,H groups attached to one or more nitrogen atoms, where n is aninteger from 1 to for example, can be employed if desired.

Where salts of the polyamines are employed, the carboxylic acid employedto make the salt can be an acid as described previously with regard tothe acid employed in preparation of the ester additive. The acidemployed to make the salt can be the same acid as that employed to makethe ester, or it may be a ditferent acid within the same general class.The examples of acids given previously with regard to the esterpreparation constitute Preferred polyamine materials are the salts of anor-' ganic carboxylic acid having 12 to 30 carbon atoms per molecule anda polyamine having the formula RNH(CH ),,NH

where R is a hydrocarbon radical containing 10 to 30 efiectivepolyamine, the following description is given:

carbon atoms and n is an integer from 2 to 6. -Mono or disalts can beemployed. Examples of suitablecarboxylic acids are, fatty. acids,naphthenic acids, rosin acids, acids produced bypartial oxidation inliquid phase of petroleum fractions etc. Examples of suitable R radicalsarethe hydrocarbon residues from such carboxylic acids. Examples ofsuitable polyamines arealltylene di-. amines such as ethylene diamine,trimethylene diamine, tetramethylene diamine, pentamethylene diamine,and hexamethylene diamine, having an R substituent on one nitrogen atom,e.g. N-decylethylene diamine, N-hexadecyl propane diamine-l,3, N-butyltetraethylene pentamine, N- octadecyl diethylene triamine, N-dibutyltetramethylene diamine, N-abietyl hexamethylene diamine, N-naphthenyl-N'-rnethyl ethylene diamine, polyethoxylated derivatives of theforegoing, etc.

Although less preferred, polyamines wherein R in the formula given inthe preceding paragraph is hydrogen can also be employed, e.g.1,2-diamino dodecane, 1,12-diamino tetradecane, diamino octadecanes,polyethoxylated derivatives of the foregoing, etc.

The invention is applicable generally to sulfur-containing lubricantswhich tend to stain various metals upon contact therewith, for examplein the use of the sulfurcontaining lubricant as a cutting fluid in theworking of ferrous metals. Examples of suitable sulfur-containinglubricants are fatty or petroleum oils containing dissolved elementalsulfur, fatty or petroleum oils which have been reacted at elevatedtemperature with a sulfurizing agent such as elemental sulfur, sulfurmonochloride, etc. V arious fatty oils are suitable for this purpose,e.g. lard oil, rapeseed oil, sperm oil, cottonseed oil, palm oil, etc.Other examples of sulfur-containing lubricants are fatty or petroleumoils containing various sulfur-containing ad ditives such as xanthateesters, metal salts of reaction products of olefins and phosphorouspentasulfide, organic trisulfides, metal salts of organic-substitutedphosphoric acids, e.g. zinc, dihexyl dithiosulfide, sulfurized olefinssuch as sulfurized terpenes, etc.

The polyarnine additive employed according to the. in-

As an example of a manner of preparation of a particularly a carboxylicacid or mixture of acids such as tallow fatty acids can be reacted withammonia to produce ammonium soaps, which are then chemically dehydratedby known means to form nitriles, the latter then being hydrogenated toform fatty amines; the; latter are reacted with acrylo nitrile to formcompounds having the formula RCH NHCH CH CN.

where R is a hydrocarbon radical of the original fatty acid, RCOOH; theresulting compounds are hydrogenated to provide amines having theformula Parts by Volume Oomponent Description Petroleum lubricating oil(Neutral distillate {Bram r iaphthtmie base crude, about 100 SUS at;

Sulfochlorinatecl methyl esters of lard oil acids (Reaction product ofesters with S 61 S content 9 Wt. percent, Cl content 9 Wt. percent).

Sulfur-containing petroleum oil (0.9 Wt. percent of elemental Sdissolved at; 140-l50 F. in neutral nnphthcutc distillate-about; 150 SUSat 100 F.).

N -tallow propylene (liarnine diuaphthenate-.

Glycerol monooleate Component D was prepared by neuptralizing naphthenicacids with a material known by the trademark "Duomeen T comprising amixture of diamines having the formula RNHCH CH CH NH where R is ahydrocarbon radical derived from tallow, the average molecular weight ofthe mixture of diamines being 320, the combining Weight being about 400however because of the presence of impurities. The preparation of suchdiamine mixtures is described in United States Patent No. 2,736,658issued February 28, 1956, to F. W. Pfohl and V. P. Gregory.

The naphthenic acids employed in the preparation of component Dconformed in preparation and properties to those sold commercially underthe trademark Sunaptic Acids C. Typical properties for such acicls'arethe following: acid number 122 mg. of KOI-I per gram, average molecularweight 415', average molecular formula 0 1-1 0 average type formula Gi-1 0 and distillation range 408 F. to 596 F./2 mm. Hg (O-96%).Component D was prepared by stirring together at room temperature, andthereby reacting, about 415 parts by weight of the naphthenic acids withslightly more than 400 parts by weight of Duomeen T. The resultingmixture of salts varied from one salt to the next not only in thediamine but also in the acid since the naphthenic acids used were also amixture of acids having varying molecular weight and chemical structure.

The composition described above was tested for its stainingcharacteristics: cc. of the composition and 10 cc. of water wereagitated together to produce a dispersion of water in the compositon; 1cc. of the dispersion was placed between two polished steel panels, andthe latter were maintained in close contact with a film of thedispersion between them for 24 hours at room temperature; the panelswere then separated, washed with naphtha, and observed.

For comparison, compositions as described above, but containing in oneinstance neither component D nor component E, in another instance 1 partby volume of component D in the absence of component E, and in anotherinstance 1 part by volume of component E in the Parts by Volume Stain 00 Heavy. 1. 0 0 Heavy. O 1.0 Heavy. 0.5 0.5 Very slight. 1. 0 1. 0 None.

These results show the necessity for both com onents to secure thebeneficial reduction instaining tendency. No significant reduction in'staining is obtained with 1 part by volume of either component alone. 0nthe other hand, a great reduction in staining is obtained with 1 part ofan equal volume mixture of the two components, and complete eliminationof staining in a very severe test is obtained with 2 parts of an equalvolume mixture.

Generally similar results are obtained using fatty acids such as oleicacid, rosin acids, or acids obtained by partial oxidation ofhydrocarbons, in place of naphthenic acids in the preparation ofcomponent D. Generally similar results are also obtained using otherspecific polyhydric alcohol esters'within the scope of the invention,for example the specific esters disclosed previously herein, and alsosorbitan monoesters of petroleum naphthenic acids having an average of21 carbon atoms per molecule, polyoxyethylene sorbitol tetraesters ofcarboxylic acids produced in liquid phase partial oxidation of petroleumlubricating oil and having an average of 18 carbon atoms per molecule,glycerol monoabietate, etc. Generaly similar results are also obtainedusing other sulfur-containing lubricants such as sulfochlorinated lardoil containing about 2 percent each of sulfur and chlorine, or theindividual component C of the abovedescribed composition, or a lubricantobtained by reacting elemental sulfur at 300 F. with a naphthenicpetroleum distillate having Saybolt Universal viscosity at 100 F. ofabout 160 seconds for 2 hours to produce an oil containing about 2Weight percent of sulfur, etc. Generally 7 similar results are alsoobtained using other polyamines or salts such as N-decyl ethylenediamine monoabietate,

N-butyl tetraethylene pentamine distearate, a mixture of' polyalkylenepolyamines having the formula z wulcmNHn where n is an integer varyingthrough the range from 6 to 10, N-octadecyl diethylene triaminetrilaurate, the specific polyamines disclosed previously herein, saltsof those polyamines with the specific carboxylic acids 'disclosedpreviously herein, etc. The various specific maacteristic is typical ofthe polyamines and salts within the scope of the invention as set forthpreviously. The essential characterisic of the ester additive isbelieved to be its ability to emulsify water in oil, a characteristicwhich is generally typical of the esters within the scope of theinvention as set forth previously.

The invention claimed is:

l. A lubricating composition consisting essentially of asulfur-containing lubricant selected from the group consisting ofpetroleum hydrocarbon oils and fatty oils, which lubricant contains atleast 1 weight'percent of sulfur and tends to stain ferrous metals uponcontact therewith, 0.1 to 5 weight percent of a partial ester of apolyhydric alcohol, said ester having hydrophile-lipophile balancewithin the approximate range from 3 to 6 and containing 14 to 56 carbonatoms per molecule, and 0.1 to 5 Weight percent of a component selectedfrom the group consisting of an acyclic polyamine containing 12 to 28carbon atoms per molecule and a salt of said polyamine with an organiccarboxylic acid containing 12 to 30 carbon atoms per molecule. 7

2. The lubricating composition of claim 1 wherein said partial ester isa monoglyceride of a naturally occurring fatty acid.

3. The lubricating compositon of claim 1 wherein said polyamine is anN-substituted alkylene diamine containing 2 to 6 carbon atoms in thealkylene group between the nitrogen atoms. a

4. The lubricating compositon of claim l wherein the sulfur-containinglubricant comprises a sulfochlorinated fatty oil.

5. The lubricating composition of claim 1 wherein the sulfur-containinglubricant comprises a sulfurized mineral oil. Y i

6. The lubricating composition of claim 1 wherein the sulfur-containinglubricant contains 1 to 5 weight percent of sulfur.

7. The lubricating compositon of claim 1 wherein said ester is presentin an amount which is capable of 'incorporation in said lubricant in theabsence of said polyamine.

8. The lubricating composition of claim 1 wherein said sulfur-containinglubricant comprises a naphthenic said carboxylic acidis'selected fromthe group consisting of naturally occurring fatty acids, rosin acids,

petroleum naphthenic acids, and acids obtained by partial oxidation ofhydrocarbon mixtures.

. References Cited in the file of this patent I UNITED STATES PATENTS2,626,240 Deutser Jan. 20, 1953 2,696,473 Sokol Dec. 7, 1954 2,736,658Pfohl et al. Feb. 28, 1956 Barnum Aug. l4, 1951 Buck a a1. July 2, 1957'

1. A LUBIRCATING COMPOSITION CONSISTING ESSENTIALLY OF ASULFUR-CONTAINING LUBRICANT SELECTED FROM THE GROUP CONSISTING OFPETROLEUM HYDROCARBON OILS AND FATTY OILS, WHICH LUBRICANT CONTAINS ATLEAST 1 WEIGHT PERCENT OF SULFUR AND TENDS TO STAIN FERROUS METALS UPONCONTACT THEREWITH, 0.1 TO 5 WEIGHT PERCENT OF A PARTIAL ESTER OF APOLYHYDRIC ALCOHOL, SAID ESTER HAVING HYDROPHILE-LIPOPHILE BALANCEWITHIN THE APPROXIMATE RANGE FROM 3 TO 6 AND CONTAINING 14 TO 56 CARBONATOMS PER MOLECULE, AND 0.1 TO 5 WEIGHT PERCENT OF A COMPONENT SELECTEDFROM THE GROUP CONSISTING OF AN ACYCLIC POLYAMINE CONTAINING 12 TO 28CARBON ATOMS PER MOLECULE AND A SALT OF SAID POLYAMINE WITH AN ORGANICCARBOXYLIC ACID CONTAINING 12 TO 30 CARBON ATOMS PER MOLECULE.